Million of vertex/edges (don´t know exactly the name)
So in light of your wrong retopo setup these are the steps you need to take.

Prep High Poly mesh
1. Turn off "show wires" and "draw all edges" on the high poly object.
2. Give this a dark color material with some soft specularity to aid in retopo work.



Prep Low Poly mesh
1. Create a new plane mesh to be your new low poly retopo object.
2. Turn on xray on the object property panel.
3. Turn on show face normals on the navigation panel in the 3d viewport.  

Prep Retopology tools
1. Turn on snap tool, on the drop down menu choose "face"
2. Turn on "snap to self"
3. Turn on "project individual elements on the surface of other object"
4. Turn on "automatic merge vertices"  

   


Learn the "F2 addon" or other addon suggested and use it to work retopology.


Here is the screen shot.